1<?php
2
3declare(strict_types=1);
4
5/*
6 * This file is part of the league/commonmark package.
7 *
8 * (c) Colin O'Dell <colinodell@gmail.com>
9 *
10 * For the full copyright and license information, please view the LICENSE
11 * file that was distributed with this source code.
12 */
13
14namespace League\CommonMark\Extension\ExternalLink;
15
16use League\CommonMark\Event\DocumentParsedEvent;
17use League\CommonMark\Extension\CommonMark\Node\Inline\Link;
18use League\Config\ConfigurationInterface;
19
20final class ExternalLinkProcessor
21{
22    public const APPLY_NONE     = '';
23    public const APPLY_ALL      = 'all';
24    public const APPLY_EXTERNAL = 'external';
25    public const APPLY_INTERNAL = 'internal';
26
27    /** @psalm-readonly */
28    private ConfigurationInterface $config;
29
30    public function __construct(ConfigurationInterface $config)
31    {
32        $this->config = $config;
33    }
34
35    public function __invoke(DocumentParsedEvent $e): void
36    {
37        $internalHosts   = $this->config->get('external_link/internal_hosts');
38        $openInNewWindow = $this->config->get('external_link/open_in_new_window');
39        $classes         = $this->config->get('external_link/html_class');
40
41        foreach ($e->getDocument()->iterator() as $link) {
42            if (! ($link instanceof Link)) {
43                continue;
44            }
45
46            $host = \parse_url($link->getUrl(), PHP_URL_HOST);
47            if (! \is_string($host)) {
48                // Something is terribly wrong with this URL
49                continue;
50            }
51
52            if (self::hostMatches($host, $internalHosts)) {
53                $link->data->set('external', false);
54                $this->applyRelAttribute($link, false);
55                continue;
56            }
57
58            // Host does not match our list
59            $this->markLinkAsExternal($link, $openInNewWindow, $classes);
60        }
61    }
62
63    private function markLinkAsExternal(Link $link, bool $openInNewWindow, string $classes): void
64    {
65        $link->data->set('external', true);
66        $this->applyRelAttribute($link, true);
67
68        if ($openInNewWindow) {
69            $link->data->set('attributes/target', '_blank');
70        }
71
72        if ($classes !== '') {
73            $link->data->append('attributes/class', $classes);
74        }
75    }
76
77    private function applyRelAttribute(Link $link, bool $isExternal): void
78    {
79        $options = [
80            'nofollow'   => $this->config->get('external_link/nofollow'),
81            'noopener'   => $this->config->get('external_link/noopener'),
82            'noreferrer' => $this->config->get('external_link/noreferrer'),
83        ];
84
85        foreach ($options as $type => $option) {
86            switch (true) {
87                case $option === self::APPLY_ALL:
88                case $isExternal && $option === self::APPLY_EXTERNAL:
89                case ! $isExternal && $option === self::APPLY_INTERNAL:
90                    $link->data->append('attributes/rel', $type);
91            }
92        }
93
94        // No rel attributes? Mark the attribute as 'false' so LinkRenderer doesn't add defaults
95        if (! $link->data->has('attributes/rel')) {
96            $link->data->set('attributes/rel', false);
97        }
98    }
99
100    /**
101     * @internal This method is only public so we can easily test it. DO NOT USE THIS OUTSIDE OF THIS EXTENSION!
102     *
103     * @param non-empty-string|list<non-empty-string> $compareTo
104     */
105    public static function hostMatches(string $host, $compareTo): bool
106    {
107        foreach ((array) $compareTo as $c) {
108            if (\strpos($c, '/') === 0) {
109                if (\preg_match($c, $host)) {
110                    return true;
111                }
112            } elseif ($c === $host) {
113                return true;
114            }
115        }
116
117        return false;
118    }
119}
120